Searching for a dipole modulation in the large-scale structure of the Universe

Several statistical anomalies in the CMB temperature anisotropies seem to defy the assumption of a homogeneous and isotropic universe. In particular, a dipole modulation has been detected both in WMAP and Planck data. We adapt the methodology proposed by Eriksen et al. (2007) on CMB data to galaxy surveys, tracing the large-scale structure. We analyse the NRAO VLA Sky Survey (NVSS) data at a resolution of ~2 degrees for three different flux thresholds: 2.5, 5.0 and 10.0 mJy respectively. No evidence of a dipole modulation is found. This result suggests that the origin of the dipole asymmetry found in the CMB cannot be assigned to secondary anisotropies produced at redshifts around z = 1. However, it could still have been generated at redshifts higher or lower, such as the integrated Sachs-Wolfe effect produced by the local structures. Other all-sky surveys, like the infrared WISE catalogue, could help to explore with a high sensitivity a redshift interval closer than the one probed with NVSS.Comment: 6 pages, 2 figures. Some minor changes have been done from the original manuscript. This paper is accepted by MNRA

Foreground influence on primordial non-Gaussianity estimates: needlet analysis of WMAP 5-year data

We constrain the amplitude of primordial non-Gaussianity in the CMB data taking into account the presence of foreground residuals in the maps. We generalise the needlet bispectrum estimator marginalizing over the amplitudes of thermal dust, free-free and synchrotron templates. We apply our procedure to WMAP 5 year data, finding fNL= 38\pm 47 (1 \sigma), while the analysis without marginalization provides fNL= 35\pm 42. Splitting the marginalization over each foreground separately, we found that the estimates of fNL are positively cross correlated of 17%, 12% with the dust and synchrotron respectively, while a negative cross correlation of about -10% is found for the free-free component.Comment: Submitted to MNRA

Wilkinson Microwave Anisotropy Probe 7-yr constraints on fNL with a fast wavelet estimator

A new method to constrain the local non-linear coupling parameter fNL based on a fast wavelet decomposition is presented. Using a multiresolution wavelet adapted to the HEALPix pixelization, we have developed a method that is 10^2 times faster than previous estimators based on isotropic wavelets and 10^3 faster than the KSW bispectrum estimator, at the resolution of the Wilkinson Microwave Anisotropy Probe (WMAP) data. The method has been applied to the WMAP 7-yr V+W combined map, imposing constraints on fNL of -69 < fNL < 65 at the 95 per cent CL. This result has been obtained after correcting for the contribution of the residual point sources which has been estimated to be fNL = 7 +/- 6. In addition, a Gaussianity analysis of the data has been carried out using the third order moments of the wavelet coefficients, finding consistency with Gaussianity. Although the constrainsts imposed on fNL are less stringent than those found with optimal estimators, we believe that a very fast method, as the one proposed in this work, can be very useful, especially bearing in mind the large amount of data that will be provided by future experiments, such as the Planck satellite. Moreover, the localisation of wavelets allows one to carry out analyses on different regions of the sky. As an application, we have separately analysed the two hemispheres defined by the dipolar modulation proposed by Hoftuft et al. (2009). We do not find any significant asymmetry regarding the estimated value of fNL in those hemispheres.Comment: 8 pages, 5 figures. Submitted and Accepted for publication in MNRA

Affine equation of state from quintessence and k-essence fields

We explore the possibility that a scalar field with appropriate Lagrangian can mimic a perfect fluid with an affine barotropic equation of state. The latter can be thought of as a generic cosmological dark component evolving as an effective cosmological constant plus a generalized dark matter. As such, it can be used as a simple, phenomenological model for either dark energy or unified dark matter. Furthermore, it can approximate (up to first order in the energy density) any barotropic dark fluid with arbitrary equation of state. We find that two kinds of Lagrangian for the scalar field can reproduce the desired behaviour: a quintessence-like with a hyperbolic potential, or a purely kinetic k-essence one. We discuss the behaviour of these two classes of models from the point of view of the cosmological background, and we give some hints on their possible clustering properties.Comment: 9 pages, 6 figures. Minor updates, accepted by CQ

Addressing disparities in European cancer outcomes: a qualitative study Protocol of the BEACON project

Introduction: Health disparities represent a crucial factor in cancer survival rates, awareness, quality of life, and mental health of people receiving a cancer diagnosis and their families. Income, education, geographic location, and ethnicity are some of the most important underlying reasons for health disparities in cancer across Europe. Costs of healthcare, access to information, psycho-oncological support options, integration of cancer research and innovative care, and multidisciplinary cancer teams are the main target areas when it comes to addressing disparities in the cancer context. As part of the Beacon Project (BEACON), we developed a protocol for a qualitative study to explore and identify any relevant reasons for cancer inequalities and disparities in Europe. Methods: Our four stakeholders namely, cancer patients, healthcare providers, researchers, and policymakers will be recruited online, facilitated by collaborative efforts with cancer organizations from various European countries, including but not limited to Italy, Croatia, Estonia, and Slovenia. Qualitative online focus group discussions for each stakeholder will be conducted and transcribed. Subsequently, thematic analysis will be used to identify reasons and aspects that may contribute to the existing disparities in cancer outcomes at various levels of engagement and from different stakeholders’ perspectives. Results from focus groups will inform a subsequent Delphi study and a SWOT analysis methodology. Discussion: Although advances in medical research, cancer screening and treatment options are constantly progressing, disparities in access to and awareness of healthcare in cancer patients are even more noticeable. Thus, mapping the capacity and capability of cancer centres in the European Union, creating decision support tools that will assist the four stakeholders’ information needs and improving the quality of European cancer centres will be the main objectives of the BEACON project. The current protocol will outline the methodological and practical procedures to conduct online focus group discussions with different stakeholders

Risk communication in clinical trials: A cognitive experiment and a survey

10.1186/1472-6947-10-55BMC Medical Informatics and Decision Making101

Anomalous variance in the WMAP data and Galactic Foreground residuals

A previous work (Monteser\'in et al. 2008) estimated the CMB variance from the three-year WMAP data, finding a lower value than expected from Gaussian simulations using the WMAP best-fit cosmological model. We repeat the analysis on the five-year WMAP data using a new estimator with lower bias and variance. Our results confirm this anomaly at higher significance, namely with a p-value of 0.31%. We perform the analysis using different exclusion masks, showing that a particular region of the sky near the Galactic plane shows a higher variance than 95.58% of the simulations whereas the rest of the sky has a lower variance than 99.96% of the simulations. The relative difference in variance between both regions is bigger than in 99.64% of the simulations. This anisotropic distribution of power seems to be causing the anomaly since the model assumes isotropy. Furthermore, this region has a clear frequency dependence between 41GHz and 61GHz or 94GHz suggesting that Galactic foreground residuals could be responsible for the anomaly. Moreover, removing the quadrupole and the octopole from data and simulations the anomaly disappears. The variance anomaly and the previously reported quadrupole and octopole alignment seem therefore to be related and could have a common origin. We discuss different possible causes and Galactic foreground residuals seem to be the most likely one. These residuals would affect the estimation of the angular power spectrum from the WMAP data, which is used to generate Gaussian simulations, giving rise to an inconsistency between the estimated and expected CMB variance. If the presence of residuals is confirmed, the estimation of the cosmological parameters could be affected.Comment: Accepted for publication in MNRAS. Analysis section rewritten. New exclusion masks are used finding a high variance region. Relation to the Quadrupole-Octopole alignment foun

Non-Gaussian bubbles in the sky

We point out a possible generation mechanism of non-Gaussian bubbles in the sky due to bubble nucleation in the early universe. We consider a curvaton scenario for inflation and assume that the curvaton field phi, whose energy density is subdominant during inflation but which is responsible for the curvature perturbation of the universe, is coupled to another field sigma which undergoes false vacuum decay through quantum tunneling. For this model, we compute the skewness of the curvaton fluctuations due to its interaction with sigma during tunneling, that is, on the background of an instanton solution that describes false vacuum decay. We find that the resulting skewness of the curvaton can become large in the spacetime region inside the bubble. We then compute the corresponding skewness in the statistical distribution of the cosmic microwave background (CMB) temperature fluctuations. We find a non-vanishing skewness in a bubble-shaped region in the sky. It can be large enough to be detected in the near future, and if detected it will bring us invaluable information about the physics in the early universe.Comment: 6 pages, 6 figure

Are Patients With Longer Emergency Department Wait Times Less Likely to Consent to Research?

Objectives: There are unique challenges to enrolling patients in emergency department (ED) clinical research studies, including the time-sensitive nature of emergency conditions, the acute care environ- ment, and the lack of an established relationship with patients. Prolonged ED wait times have been asso- ciated with a variety of adverse effects on patient care. The objective of this study was to assess the effect of ED wait times on patient participation in ED clinical research. The hypothesis was that increased ED wait times would be associated with reduced ED clinical research consent rates. Methods: This was a retrospective cohort study of all patients eligible for two diagnostic clinical research studies from January 1, 2008, through December 31, 2008, in an urban academic ED. Sex, age, race, study eligibility, and research consent decisions were recorded by trained study personnel. The wait times to registration and to be seen by a physician were obtained from administrative databases and compared between consenters and nonconsenters. An analysis of association between patient wait times for the outcome of consent to participate was performed using a multivariate logistic regression model. Results: A total of 903 patients were eligible for enrollment and were asked for consent. Overall, 589 eligible patients (65%) gave consent to research participation. The consent rates did not change when patients were stratified by the highest and lowest quartile wait times for both time from arrival to regis- tration (68% vs. 65%, p = 0.35) and time to be seen by a physician (65% vs. 66%, p = 0.58). After adjusting for patient demographics (age, race, and sex) and study, there was still no relationship between wait times and consent (p > 0.4 for both wait times). Furthermore, median time from arrival to registration did not differ between those who consented to participate (15 minutes; interquartile range [IQR] = 9 to 36 minutes) versus those who did not (15.5 minutes; IQR = 10 to 39 minutes; p = 0.80; odds ratio [OR] = 1.00, 95% confidence interval [CI] = 0.99 to 1.01). Similarly, there was no difference in the median time to be seen by a physician between those who consented (25 minutes; IQR = 15 to 55 minutes) versus those who did not (25 minutes; IQR = 15 to 56 minutes; p = 0.70; OR = 1.00, 95% CI = 0.99 to 1.01). Conclusions: Regardless of wait times, nearly two-thirds of eligible patients were willing to consent to diagnostic research studies in the ED. These findings suggest that effective enrollment in clinical research is possible in the ED, despite challenges with prolonged wait times